CN112449617B - Machining device and cutting method - Google Patents
Machining device and cutting method Download PDFInfo
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- CN112449617B CN112449617B CN201980048586.XA CN201980048586A CN112449617B CN 112449617 B CN112449617 B CN 112449617B CN 201980048586 A CN201980048586 A CN 201980048586A CN 112449617 B CN112449617 B CN 112449617B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B7/00—Automatic or semi-automatic turning-machines with a single working-spindle, e.g. controlled by cams; Equipment therefor; Features common to automatic and semi-automatic turning-machines with one or more working-spindles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B1/00—Methods for turning or working essentially requiring the use of turning-machines; Use of auxiliary equipment in connection with such methods
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B25/00—Accessories or auxiliary equipment for turning-machines
- B23B25/06—Measuring, gauging, or adjusting equipment on turning-machines for setting-on, feeding, controlling, or monitoring the cutting tools or work
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q15/00—Automatic control or regulation of feed movement, cutting velocity or position of tool or work
- B23Q15/007—Automatic control or regulation of feed movement, cutting velocity or position of tool or work while the tool acts upon the workpiece
- B23Q15/12—Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23B—TURNING; BORING
- B23B2250/00—Compensating adverse effects during turning, boring or drilling
- B23B2250/16—Damping of vibrations
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/41—Servomotor, servo controller till figures
- G05B2219/41256—Chattering control
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- Mechanical Engineering (AREA)
- Automatic Control Of Machine Tools (AREA)
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Abstract
The rotation mechanism (8) rotates a spindle (2a) to which a cutting tool (10) or a workpiece (6) is attached. A rotation control unit (21) controls the rotation of the main shaft (2a) by the rotation mechanism (8). The feed mechanism (7) moves the cutting tool (10) relative to the workpiece (6). The rotation control unit (21) alternately executes acceleration control for accelerating the rotation of the spindle so that the speed change ratio, which is the ratio of the current cutting speed to the cutting speed immediately before one rotation at the same rotational position, becomes a first value or more larger than 1, and deceleration control for decelerating the rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
Description
Cross Reference to Related Applications
The present application claims priority based on japanese patent application No. 2018-149918, filed on 8/9/2018, and the entire contents of the application are incorporated by reference into the specification of the present application.
Technical Field
The present disclosure relates to a machining apparatus and a cutting machining method.
Background
Conventionally, there are machining apparatuses that: that is, a machining device is configured to attach a cutting tool or a workpiece to a rotatable spindle, rotate the spindle, and perform machining by bringing the workpiece into contact with the cutting tool. In this machining apparatus, "regenerative chatter vibration" in which the material to be cut and/or the cutting tool vibrates may be generated.
"regenerative flutter" is a self-excited vibration: the vibration generated during one-pass cutting (one-pass in a multi-edge tool) remains as a waviness of the machined surface, and the vibration is self-excited vibration regenerated as a change in the cutting thickness during current cutting. Therefore, a closed circuit (loop) is configured in which the cutting force changes and vibration occurs again, and when the circuit gain increases, the vibration increases and becomes intense chattering vibration. The "regenerative chattering vibration" may not only deteriorate the finishing accuracy of the machined surface, but also may cause a defect in the cutting tool.
If the spindle rotational speed, that is, the cutting speed is controlled so that the cutting speed before one rotation at a certain rotational position (rotational angle) is sufficiently different from the current cutting speed, the regenerative chatter vibration is not enhanced. Patent document 1 discloses a method of suppressing "chatter vibration" by changing the rotational speed of a spindle at a short cycle while keeping the feed speed of a cutting tool constant when turning is performed on a workpiece.
(Prior art document)
(patent literature)
Patent document 1: japanese laid-open patent publication No. S49-105277
Disclosure of Invention
(problems to be solved by the invention)
When the spindle rotation speed is periodically changed, the ratio of the current speed to the speed before one rotation is close to 1 before and after switching between increase and decrease of the rotation speed. Conventionally, in order to suppress the regenerative chatter vibration, the spindle rotation speed is periodically changed by a triangular wave change pattern (pattern), but the applicant of the present invention has found that the regenerative chatter vibration may occur before and after the rotation speed reaches the maximum value as a result of analyzing the triangular wave change pattern. The applicant has repeatedly studied the periodic variation pattern of the spindle rotation speed and determined a variation pattern that can effectively suppress the regenerative chatter vibration.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a cutting technique that effectively suppresses regenerative chatter vibration.
(measures taken to solve the problems)
In order to solve the above problem, a machining device according to an aspect of the present application includes: a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached; a rotation control unit for controlling rotation of the spindle by the rotation mechanism; and a feed mechanism for moving the cutting tool relative to the material to be cut. The rotation control unit alternately performs acceleration control for accelerating rotation of the spindle so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before rotation at the same rotation position, becomes a first value or more larger than 1, and deceleration control for decelerating rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
Another embodiment of the present invention is a cutting method. The method comprises the following steps: a rotation control step of controlling rotation of a spindle to which a cutting tool or a workpiece is attached; and a machining step of moving the cutting tool relative to the workpiece while the spindle is rotating, and performing machining by the cutting tool. The rotation control step alternately executes acceleration control for accelerating rotation of the spindle so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before the rotation, at the same rotation position becomes a first value or more larger than 1, and deceleration control for decelerating rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
In addition, any combination of the above constituent elements, and conversion of the expression of the present application between a method, an apparatus, a system, and the like are effective as a mode of the present disclosure.
Drawings
Fig. 1 is a diagram showing a structure of a processing apparatus according to an embodiment.
Fig. 2 (a) to (c) are diagrams showing simulation results when the spindle rotation speed is controlled in a triangular wave variation pattern.
Fig. 3 (a) to (c) are diagrams showing simulation results when the spindle rotation speed is controlled in a triangular wave variation pattern.
Fig. 4 (a) to (c) are diagrams showing simulation results when the spindle rotation speed is controlled in the variation pattern of the embodiment.
Fig. 5 (a) to (c) are diagrams showing simulation results when the spindle rotation speed is controlled in the variation pattern of the modification.
Detailed Description
Fig. 1 shows a schematic structure of a processing apparatus 1 according to an embodiment. The machining apparatus 1 is a cutting apparatus that performs turning by bringing a cutting edge of a cutting tool 10 into contact with a workpiece 6. The machining apparatus 1 includes a headstock 2 and a tailstock 3 for rotatably supporting a workpiece 6 on a base 5, and a tool rest 4 for supporting a cutting tool 10. The rotation mechanism 8 is provided inside the head stock 2 and rotates the spindle 2a to which the workpiece 6 is attached. The feed mechanism 7 is provided on the base 5 for moving the cutting tool 10 relative to the material 6 to be cut. In the machining apparatus 1, the feed mechanism 7 moves the tool rest 4 in the X-axis, Y-axis, and Z-axis directions, thereby moving the cutting tool 10 relative to the workpiece 6. Here, the X-axis direction is a cutting direction that is horizontal and orthogonal to the axial direction of the workpiece 6, the Y-axis direction is a cutting direction that is vertical, and the Z-axis direction is a feeding direction that is parallel to the axial direction of the workpiece 6.
The control unit 20 includes: a rotation control unit 21 that controls rotation of the main shaft 2a by the rotation mechanism 8; and a movement control unit 22 that performs machining by the cutting tool 10 by bringing the cutting tool 10 into contact with the workpiece 6 by the feed mechanism 7 during rotation of the spindle 2 a. The machining device 1 may be an NC (numerical control) machine tool. The rotation mechanism 8 and the feed mechanism 7 are configured to have driving units such as motors, respectively, and the rotation control unit 21 and the movement control unit 22 control the operations of the rotation mechanism 8 and the feed mechanism 7 by adjusting power supplied to the driving units, respectively.
In the machining device 1 according to the embodiment, the workpiece 6 is attached to the spindle 2a and rotated by the rotation mechanism 8, but in another example, the cutting tool 10 may be attached to the spindle 2a and rotated by the rotation mechanism 8. The feed mechanism 7 may move the cutting tool 10 relative to the workpiece 6, and may have a mechanism for moving at least one of the cutting tool 10 and the workpiece 6.
In such a processing apparatus 1, the following is known: if the current cutting speed at a certain rotational position is sufficiently different from the cutting speed before one rotation, the regenerative chatter vibration does not progress. The present applicant has studied a change pattern of the spindle rotational speed that suppresses the progress of the regenerative chatter vibration, taking into account the ratio of the current cutting speed to the cutting speed immediately before one revolution. Hereinafter, the ratio of the current cutting speed to the cutting speed before one rotation at the same rotational position is referred to as a "speed change ratio".
Before describing the change pattern used in the embodiment, a change pattern of a triangular wave used in the related art to suppress the progress of regenerative chatter vibration is examined.
Fig. 2 (a) shows a change pattern of a triangular wave of the spindle rotational speed. The cycle of the change pattern was 2 seconds, and the speed was changed at a constant acceleration and a constant deceleration within a range of a minimum value of 1400rpm and a maximum value of 2600 rpm. The acceleration period from the minimum value to the maximum value is equal to the deceleration period from the maximum value to the minimum value, and is 1 second each.
Fig. 2 (b) shows a transition pattern of the speed change ratio. As described above, the speed change ratio is derived from the following equation.
Speed variation ratio (current cutting speed/cutting speed before one rotation)
In the variation pattern shown in fig. 2 (a), the following characteristics are shown: the speed change ratio gradually decreases in a state exceeding 1 during an acceleration period of the rotation of the main shaft, and gradually decreases in a state below 1 during a deceleration period of the rotation of the main shaft.
Fig. 2 (c) shows the change in the acceleration of the chattering vibration. The simulation results show that the acceleration of chatter vibration increases from time Ta to just before time Tb, and chatter vibration progresses. At time Tb, the acceleration of the chattering vibration starts to decrease, which indicates that the suppression effect of the chattering vibration starts to be obtained at time Tb. The applicant of the present invention examined the pattern of transition of the speed change ratio shown in fig. 2 (b) that the cause of the increase in the vibration acceleration is related to the value of the speed change ratio in the period Ia-b from the time Ta to the time Tb.
In fig. 2 (b), the speed change ratio at time Ta is Tha (> 1), and the speed change ratio at time Tb is Thb (< 1). Since the acceleration of the chattering vibration starts increasing at time Ta and starts decreasing at time Tb, the speed variation ratio of Thb or more and Tha or less cannot suppress the progress of the chattering vibration. The present applicant studied the relationship between Tha and Thb, and as a result, found that a value obtained by subtracting 1 from Tha (Tha-1) and a value obtained by subtracting Thb from 1 (1-Thb) have an approximately equal relationship.
The vicinity of the maximum value and the vicinity of the minimum value of the spindle rotation speed are compared, and the regenerative chatter vibration is generated in the vicinity of the maximum value of the spindle rotation speed and is not generated in the vicinity of the minimum value of the spindle rotation speed. This is considered to be because the regenerative chatter vibration takes a certain amount of time to develop after the acceleration of the chatter vibration starts to increase, and because the speed change is shorter than the period between Thb and Tha near the minimum value of the main shaft rotational speed, the regenerative chatter vibration does not occur.
On the other hand, in the vicinity of the maximum value of the main shaft rotation speed, it is estimated from the simulation result of the vibration acceleration shown in fig. 2 (c) that the speed change ratio is sufficiently longer than the period Ia-b between Thb and Tha, and the regenerative chatter vibration can be advanced. As is clear from the above discussion, when the spindle rotational speed is controlled in the triangular wave change pattern shown in fig. 2 (a), the period Ia-b in which the speed change ratio is about 1 becomes long near the maximum value, and therefore the generation of the regenerative chatter vibration cannot be suppressed.
Fig. 3 and 4 show simulation results comparing the change pattern of the triangular wave with the change pattern of the embodiment. The period of the change pattern of both was 3 seconds.
Fig. 3 (a) shows a change pattern of a triangular wave of the spindle rotational speed. The change pattern makes an acceleration period from a minimum value to a maximum value equal to a deceleration period from the maximum value to the minimum value.
Fig. 3 (b) shows a transition pattern of the speed change ratio, and fig. 3 (c) shows a change in the vibration amount of the chattering vibration. In the vicinity of the maximum value of the spindle rotation speed, chatter vibration starts to increase at the timing (timing) when the speed variation ratio falls to Th _ h (> 1), and the chatter vibration starts to converge at the timing (timing) when the speed variation ratio falls to Th _ l (< 1). Fig. 3 (c) shows a case where chatter vibration progresses in a period Ih-l from a timing (timing) at which the speed change ratio becomes Th _ h (> 1) to a timing (timing) at which the speed change ratio becomes Th _ l (< 1).
Fig. 4 (a) shows a pattern of variation in spindle rotational speed in the embodiment. The change pattern of the spindle rotational speed of the embodiment has a waveform pattern in which the length of the acceleration period from the minimum value to the maximum value is equal to the length of the deceleration period from the maximum value to the minimum value. In this change pattern, the acceleration period and the deceleration period are set to 1.5 seconds, respectively, and the acceleration period and the deceleration period are alternately repeated.
Fig. 4 (b) shows a transition pattern of the speed change ratio in the change pattern of the embodiment. The rotation control unit 21 has a function of alternately executing acceleration control for accelerating the rotation of the main shaft 2a to set the speed change ratio to a first value (V1) larger than 1 and deceleration control for decelerating the rotation of the main shaft 2a to set the speed change ratio to a second value (V2) smaller than 1.
The rotation control unit 21 maintains the speed change ratio at V1 for at least part of the acceleration period of the main shaft rotation, and maintains the main shaft change ratio at V2 for at least part of the deceleration period of the main shaft rotation. The rotation control unit 21 of the embodiment maintains the speed change ratio at V1 after changing from V2 to V1 in the acceleration period of the main shaft rotation, and maintains the speed change ratio at V2 after changing from V1 to V2 in the deceleration period of the main shaft rotation. Preferably, the ratio of the time during which the speed change ratio is changed from V2 to V1 to the time during which the speed change ratio is maintained at V1 in the acceleration period is 1/7 or less. Similarly, it is preferable that the ratio of the time during which the speed change ratio is changed from V1 to V2 to the time during which the speed change ratio is maintained at V2 be 1/7 or less. In order to equalize the lengths of the acceleration period and the deceleration period and to form a continuous profile (profile), the rotation control unit 21 may set V1 and V2 such that the product of V1 and V2 is 1. For example, if V1 is set to 1.03, V2 can be set to 1/1.03, i.e., the reciprocal of V1.
In fig. 4 (b), chattering vibration may occur at a speed change ratio of above Th _ l and below Th _ h. The threshold values Th _ l and Th _ h can be calculated by simulation or derived by experiment. Further, referring to the simulation results shown in (a) to (c) of fig. 2, the time Tb at which the flutter suppression effect starts to be obtained can be derived, whereby the speed change ratio Thb (Th _ l) at that time can be uniquely derived, and since (Tha (Th _ h) -1) and (1-Thb (Th _ l)) have an equal relationship as described above, (Th _ l) can be determined, then Tha (Th _ h) can be determined by determining Thb (Th _ l). In this way, the threshold values Th _ l and Th _ h can be derived from the simulation result. The rotation control unit 21 sets the first value (V1) during acceleration control to be higher than the threshold Th _ h, and sets the second value (V2) during deceleration control to be lower than the threshold Th _ l.
Similarly, in the variation pattern shown in fig. 4 (a), the period in which the speed variation ratio is equal to or greater than Th _ l and equal to or less than Th _ h occurs in the vicinity of the maximum value and the minimum value of the spindle rotational speed. However, the rotation control unit 21 can make the period during which the speed change ratio is equal to or greater than Th _ l and equal to or less than Th _ h by alternately performing acceleration control in which the acceleration of the spindle rotation is continuously increased to make the speed change ratio the first value (V1) and deceleration control in which the acceleration of the spindle rotation is continuously decreased to make the speed change ratio the second value (V2). This difference is clearly seen when compared with the period Ih-l in the triangular wave change mode (see fig. 3 (b)).
The rotation control unit 21 may alternatively perform the acceleration control and the deceleration control so that the period during which the speed change ratio is equal to or greater than Th _ l and equal to or less than Th _ h can be shortened to such an extent that chattering vibration cannot progress. For example, the machining device 1 that performs acceleration control and deceleration control such that the speed change ratio V1 is maintained during the acceleration period and the speed change ratio V2 is maintained during the deceleration period even if the speed change ratio is instantaneously smaller than V1 during the acceleration period or the speed change ratio is instantaneously larger than V2 during the deceleration period due to a change in the power supply voltage or the like is included in the scope of the present application.
Fig. 4 (c) shows a change in the vibration amount of the chattering vibration. Simulation results of the variation pattern of the embodiment show that the generation of chatter vibration can be effectively suppressed. The rotation control section 21 performs acceleration control in such a manner that the speed variation ratio maintains the first value (V1) at all rotational positions of the entire rotation of the spindle rotation axis, and performs deceleration control in such a manner that the speed variation ratio maintains the second value (V2) at all rotational positions of the entire rotation of the spindle rotation axis. Therefore, in the acceleration control based on the main shaft rotation speed of the rotation control unit 21, the current speed is V1 (> Th — h) times the speed before one rotation at all the rotation positions, and thus the occurrence of the regenerative chattering vibration can be suppressed. In the deceleration control based on the main shaft rotation speed of the rotation control unit 21, the current speed is V2 (< Th _ l) times the speed before one rotation at all the rotation positions, and thus the occurrence of the regenerative chatter vibration can be suppressed.
In this way, in the machining device 1, the rotation control unit 21 alternately performs acceleration control and deceleration control of the spindle rotation speed, thereby suppressing the occurrence of regenerative chatter vibration. This makes it possible to suppress tool wear and achieve machining with excellent finishing accuracy when the finished surface is always left. The present applicant has found, by performing various simulations, that the effect of suppressing the occurrence of the regenerative chatter vibration is particularly high in a change pattern having a long period, for example, a change pattern having a period of 1 second or more.
The present application has been described above based on the embodiments. It will be understood by those skilled in the art that this embodiment is an example, and various modifications may be made by combining each member and each process, and these modifications also fall within the scope of the present application. Although the lengths of the acceleration period and the deceleration period are set to be equal in the embodiment, the lengths of the acceleration period and the deceleration period may be different from each other.
In the embodiment, the rotation control unit 21 alternately executes acceleration control for accelerating the rotation of the main shaft 2a at a speed change ratio of a first value (V1) and deceleration control for decelerating the rotation of the main shaft 2a at a speed change ratio of a second value (V2). In the modification, the rotation control unit 21 may alternately execute acceleration control for accelerating the rotation of the main shaft 2a to make the speed change ratio equal to or greater than the first value (V1) and deceleration control for decelerating the rotation of the main shaft 2a to make the speed change ratio equal to or less than the second value (V2). In the acceleration control of the spindle rotational speed, the current speed is equal to or more than V1 times the speed before one revolution, and therefore, the occurrence of regenerative chatter vibration can be suppressed, and in the deceleration control, the current speed is equal to or less than V2 times the speed before one revolution, and therefore, the occurrence of regenerative chatter vibration can also be suppressed. If the period during which the speed change ratio is equal to or greater than Th _ l and equal to or less than Th _ h can be shortened, another control may be performed between the acceleration control in which the speed change ratio is equal to or greater than V1 and the deceleration control in which the speed change ratio is equal to or less than V2.
Fig. 5 (a) shows a variation pattern of the spindle rotation speed in the modification. The variation pattern of the spindle rotational speed in the modification has a waveform pattern in which the length of the acceleration period from the minimum value to the maximum value is equal to the length of the deceleration period from the maximum value to the minimum value. In this change pattern, the acceleration period and the deceleration period are set to 1 second, respectively, and the acceleration period and the deceleration period are alternately repeated. In the modification, as in the embodiment, the rotation control unit 21 performs acceleration control in which the average acceleration in the second half of the acceleration period during which the main shaft rotates is larger than the average acceleration in the first half, and performs deceleration control in which the average deceleration in the first half of the deceleration period during which the main shaft rotates is larger than the average deceleration in the second half. Here, the first half and the second half mean the first half and the second half of the period when the period is exactly divided into two halves.
As shown in fig. 5 (a), the rotation control unit 21 increases the acceleration of the spindle rotation at time Tc during the acceleration period. Further, the rotation control section 21 reduces the deceleration of the rotation of the main shaft at the time Td during the deceleration period. Therefore, the average acceleration in the second half becomes larger than the average acceleration in the first half during the acceleration period, and the average deceleration in the first half becomes larger than the average deceleration in the second half during the deceleration period.
The applicant has obtained the following insight: when the spindle rotation speed is controlled in the triangular wave change pattern shown in fig. 2 (a), the period Ia-b in which the speed change ratio is about 1 in the vicinity of the maximum value becomes long, and therefore the occurrence of regenerative chatter vibration cannot be suppressed. From this finding, it was found that the period in which the speed change ratio is about 1 in the vicinity of the maximum value can be shortened by making the average acceleration in the second half of the acceleration period in which the spindle rotates larger than the average acceleration in the first half and making the average deceleration in the first half of the deceleration period in which the spindle rotates larger than the average deceleration in the second half.
Fig. 5 (b) shows a transition pattern of the speed change ratio in the change pattern of the spindle rotational speed of the modification. As shown in fig. 5 (a), the rotation control unit 21 can make the period in which the speed change ratio is about 1 very short in the vicinity of the maximum value of the spindle rotation speed by alternately performing the acceleration control and the deceleration control. As described above, in the modification, the rotation control unit 21 alternately performs the acceleration control of gradually increasing the acceleration of the rotation of the main shaft by one or more times during the acceleration period of the rotation of the main shaft and the deceleration control of gradually decreasing the deceleration of the rotation of the main shaft by one or more times during the deceleration period of the rotation of the main shaft, thereby effectively suppressing the occurrence of chatter vibration. Here, the stepwise increase of the acceleration means a case where the acceleration is changed to a larger acceleration after a certain period, that is, a case where the acceleration is intermittently increased. The stepwise decrease of the deceleration refers to a case where the deceleration is changed to a smaller deceleration after a certain period, or a case where the deceleration is intermittently decreased.
The outline of the embodiment of the present application is as follows.
A machining device according to an aspect of the present application includes: a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached; a rotation control unit for controlling rotation of the spindle by the rotation mechanism; and a feed mechanism for moving the cutting tool relative to the material to be cut. The rotation control unit alternately performs acceleration control for accelerating rotation of the spindle so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before the same rotation position, becomes a first value or more larger than 1, and deceleration control for decelerating rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
According to this aspect, the rotation control unit controls the rotation of the main shaft based on the speed variation ratio, thereby effectively suppressing the occurrence of regenerative chatter vibration. The rotation control unit may execute acceleration control for increasing the average acceleration in the second half of the acceleration period of the rotation of the main shaft to be larger than the average acceleration in the first half, and may execute deceleration control for increasing the average deceleration in the first half of the deceleration period of the rotation of the main shaft to be larger than the average deceleration in the second half.
The rotation control unit may maintain the speed change ratio at a first value in at least a part of an acceleration period of the rotation of the main shaft, and maintain the speed change ratio at a second value in at least a part of a deceleration period of the rotation of the main shaft. The rotation control unit may maintain the speed change ratio at the first value after changing the speed change ratio from the second value to the first value in an acceleration period of the rotation of the main shaft, and maintain the speed change ratio at the second value after changing the speed change ratio from the first value to the second value in a deceleration period of the rotation of the main shaft.
The rotation control unit may alternately perform acceleration control for continuously increasing the acceleration of the rotation of the main shaft and deceleration control for continuously decreasing the deceleration of the rotation of the main shaft. Further, the rotation control unit may alternately execute acceleration control for increasing the acceleration of the rotation of the main shaft by one or more times in a stepwise manner during the acceleration period of the rotation of the main shaft and deceleration control for decreasing the deceleration of the rotation of the main shaft by one or more times in a stepwise manner during the deceleration period of the rotation of the main shaft.
A cutting method according to another aspect of the present application includes: a rotation control step of controlling rotation of a spindle to which a cutting tool or a workpiece is attached; and a machining step of moving the cutting tool relative to the workpiece while the spindle is rotating, and performing machining by the cutting tool. The rotation control step alternately executes acceleration control for accelerating rotation of the spindle so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before the rotation, at the same rotation position becomes a first value or more larger than 1, and deceleration control for decelerating rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
(availability in industry)
The application can be applied to the processing field.
(description of reference numerals)
1: a processing device; 2 a: a main shaft; 6: a material to be cut; 7: a feed mechanism; 8: a rotation mechanism;
10: a cutting tool; 20: a control unit; 21: a rotation control unit; 22: movement control unit
Claims (8)
1. A processing device, comprising:
a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached;
a rotation control unit configured to alternately execute acceleration control for accelerating rotation of the main shaft by the rotation mechanism and deceleration control for decelerating rotation of the main shaft by the rotation mechanism; and
a feed mechanism for moving the cutting tool relative to the material to be cut,
the rotation control unit maintains a speed change ratio, which is a ratio of a current cutting speed at the same rotation position to a cutting speed immediately before one rotation, at a first value greater than 1 during at least a part of an acceleration period of the rotation of the spindle, and maintains the speed change ratio at a second value less than 1 during at least a part of a deceleration period of the rotation of the spindle, thereby suppressing the occurrence of chatter vibration.
2. The processing device according to claim 1,
the rotation control unit maintains the speed change ratio at the first value after changing the speed change ratio from the second value to the first value during an acceleration period of the rotation of the main shaft, and maintains the speed change ratio at the second value after changing the speed change ratio from the first value to the second value during a deceleration period of the rotation of the main shaft.
3. Machining device according to claim 1 or 2,
the rotation control unit alternately executes acceleration control for continuously increasing the acceleration of the rotation of the main shaft and deceleration control for continuously decreasing the deceleration of the rotation of the main shaft.
4. A processing device, comprising:
a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached;
a rotation control unit configured to alternately execute acceleration control for accelerating rotation of the main shaft by the rotation mechanism and deceleration control for decelerating rotation of the main shaft by the rotation mechanism; and
a feed mechanism for moving the cutting tool relative to the material to be cut,
the rotation control unit continuously increases the acceleration of the rotation of the spindle during an acceleration period of the rotation of the spindle so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before the rotation at the same rotational position, becomes a first value or more larger than 1, and continuously decreases the deceleration of the rotation of the spindle during a deceleration period of the rotation of the spindle so that the speed change ratio becomes a second value or less smaller than 1.
5. A processing device, comprising:
a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached;
a rotation control unit configured to alternately execute acceleration control for accelerating rotation of the spindle by the rotation mechanism and deceleration control for decelerating rotation of the spindle by the rotation mechanism; and
a feed mechanism for moving the cutting tool relative to the material to be cut,
the rotation control unit increases the acceleration of the rotation of the main shaft one or more times stepwise in an acceleration period of the rotation of the main shaft so that a speed change ratio, which is a ratio of a current cutting speed to a cutting speed immediately before the rotation, at the same rotational position becomes a first value or more larger than 1, and decreases the deceleration of the rotation of the main shaft one or more times stepwise in a deceleration period of the rotation of the main shaft so that the speed change ratio becomes a second value or less smaller than 1.
6. A processing device, comprising:
a rotation mechanism for rotating a spindle to which a cutting tool or a workpiece is attached;
a rotation control unit for controlling rotation of the spindle by the rotation mechanism; and
a feed mechanism for moving the cutting tool relative to the material to be cut,
in a machining device in which chatter vibration may occur when a speed change ratio, which is a ratio of a current cutting speed to a cutting speed before one rotation at the same rotational position, is equal to or lower than a first threshold value larger than 1 and equal to or higher than a second threshold value smaller than 1,
the rotation control unit alternately performs acceleration control for accelerating rotation of the main shaft to set the speed change ratio to a first value greater than 1 or a second value smaller than 1 by decelerating the rotation of the main shaft.
7. The processing device according to claim 6,
the rotation control unit continuously or stepwise increases the acceleration of the rotation of the main shaft during an acceleration period of the rotation of the main shaft, and continuously or stepwise decreases the deceleration of the rotation of the main shaft during a deceleration period of the rotation of the main shaft.
8. A cutting work method comprising:
a rotation control step of alternately executing acceleration control for accelerating rotation of a spindle to which a cutting tool or a workpiece is attached and deceleration control for decelerating rotation of the spindle; and
a machining step of performing machining by a cutting tool by moving the cutting tool relative to a workpiece while rotating a spindle,
the rotation control step maintains a speed change ratio, which is a ratio of a current cutting speed to a cutting speed before one rotation at the same rotational position, at a first value larger than 1 during at least a part of an acceleration period of the rotation of the spindle, and maintains the speed change ratio at a second value smaller than 1 during at least a part of a deceleration period of the rotation of the spindle, thereby suppressing the generation of chatter vibration.
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| PCT/JP2019/026969 WO2020031582A1 (en) | 2018-08-09 | 2019-07-08 | Machining device and cutting method |
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| CN105739438A (en) * | 2016-04-28 | 2016-07-06 | 上海交通大学 | Method for intelligently inhibiting machining vibration |
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| JP6674403B2 (en) | 2017-03-13 | 2020-04-01 | 本田技研工業株式会社 | Vehicle with fuel cell |
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| JP2005144580A (en) * | 2003-11-13 | 2005-06-09 | Hideyuki Ohashi | Machining method and device |
| CN102554685A (en) * | 2010-10-13 | 2012-07-11 | 大隈株式会社 | Vibration suppressing method and vibration suppressing device for use in machine tool |
| JP2012130997A (en) * | 2010-12-22 | 2012-07-12 | Okuma Corp | Machining method in machine tool |
| WO2014064953A1 (en) * | 2012-10-23 | 2014-05-01 | エヌティーエンジニアリング株式会社 | Method for suppressing chatter of operating machine |
| CN105204443A (en) * | 2014-05-21 | 2015-12-30 | Dmg森精机株式会社 | Method Of Calculating Stable Spindle Rotation Number Capable Of Suppressing Chatter Vibration, Method Of Informing The Same, Method Of Controlling Spindle Rotation Number, And Method Of Editing Nc Program, And Apparatus Therefor |
| JP2016163918A (en) * | 2015-03-06 | 2016-09-08 | 国立大学法人 東京大学 | Machine tool and processing method of workpiece |
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| CN106970593A (en) * | 2017-04-18 | 2017-07-21 | 西安交通大学 | It is a kind of that the method that processing flutter suppresses online is realized by speed of mainshaft intelligent control |
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| JPWO2020031582A1 (en) | 2020-09-03 |
| DE112019003996B4 (en) | 2024-04-18 |
| CN112449617A (en) | 2021-03-05 |
| WO2020031582A1 (en) | 2020-02-13 |
| JP6775237B2 (en) | 2020-10-28 |
| US20210154746A1 (en) | 2021-05-27 |
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